Field of the Invention
Exemplary embodiments of the present disclosure relate to a supercritical CO2 generation system, and more particularly, to a supercritical CO2 generation system capable of improving power generation efficiency of a system.
Description of the Related Art
As a necessity to efficiently produce power is increasing more and more and a movement to reduce pollutant emissions is being activated more and more, various attempts to increase power production while reducing the pollutant emissions have been conducted internationally. As one of the attempts, research and development into a power generation system using supercritical CO2 as a working fluid as disclosed in Japanese Patent Laid-Open Publication No. 2012-145092 has been actively conducted.
The supercritical CO2 has a density similar to a liquid state and viscosity similar to gas, such that apparatuses may be miniaturized and power consumption required to compress and circulate a fluid may be minimized. Meanwhile, the supercritical CO2 having critical points of 31.4° C. and 72.8 atmosphere are even lower than water having critical points of 373.95° C. and 217.7 atmosphere and therefore may very easily be handled. The supercritical CO2 generation system shows pure power generation efficiency of about 45% when being operated at 550° C. and has a 20% increase in power generation efficiency compared to the existing steam cycle and reduces a size of a turbo apparatus to a tenth.
However, when the existing supercritical CO2 generation system uses a turbine having high RPM in terms of characteristics of a cycle, an output of the turbine needs to be converted into RPM suitable for a power generator using a torque converter, a gear box, etc., and then transferred. Alternatively, the existing supercritical CO2 generation system needs to convert a frequency of generated power using an inverter, thereby generating a constant output frequency. Therefore, the existing supercritical CO2 generation system is highly likely to lead to a power loss and reduction in efficiency in several parts of the cycle and increase costs due to additional parts and processes.
(Patent Document 1) Japanese Patent Laid-open Publication No. 2012-145092 (Published on Aug. 2, 2012).